The present invention generally relates to media products for receiving printed images thereon. More particularly, the invention described herein involves image-receiving sheet materials each having at least one ink-receiving layer with specialized and distinctive ingredients therein that provide a number of important benefits. These benefits include but are not limited to a high degree of compatibility between the ink materials being delivered and the ink-receiving layer under consideration, rapid drying times, a high level of water-fastness, the generation of smear-fast printed images, the control of ink-coalescence (defined below), the attainment of uniform gloss levels, a desirable level of consistency regarding the overall surface characteristics of the media products, along with other benefits relating to image quality. As will be discussed herein, these benefits are simultaneously achieved in the present invention through the use of some very special material combinations including but not limited to carefully-chosen pigment compounds, a specially-selected group of binders employed in combination, and the incorporation of a distinctive ink fixative (e.g. ink fixing agent) which is especially compatible with the chosen pigment(s). Further information regarding these important characteristics will be presented in greater detail below.
Substantial developments have been made in the field of electronic printing technology. A wide variety of highly-efficient printing systems currently exist which are capable of dispensing ink in a rapid and accurate manner. Thermal inkjet systems are especially important in this regard. Printing units using thermal inkjet technology basically involve an apparatus which includes at least one ink reservoir chamber in fluid communication with a substrate (preferably made of silicon [Si] and/or other comparable materials) having a plurality of thin-film heating resistors thereon. The substrate and resistors are maintained within a structure that is conventionally characterized as a “printhead”. Selective activation of the resistors causes thermal excitation of the ink materials stored inside the reservoir chamber and expulsion thereof from the printhead. Representative thermal inkjet systems are discussed in, for example, U.S. Pat. No. 4,771,295 to Baker et al. and U.S. Pat. No. 5,278,584 to Keefe et al. which are both incorporated herein by reference.
The ink delivery systems described above (and comparable printing units using thermal inkjet technology) typically include an ink containment unit (e.g. a housing, vessel, or tank) having a self-contained supply of ink therein in order to form an ink cartridge. In a standard ink cartridge, the ink containment unit is directly attached to the remaining components of the cartridge to produce an integral and unitary structure wherein the ink supply is considered to be “on-board” as shown in, for example, U.S. Pat. No. 4,771,295 to Baker et al. However, in other cases, the ink containment unit is provided at a remote location within the printer, with the ink containment unit being operatively connected to and in fluid communication with the printhead using one or more ink transfer conduits. These particular systems are conventionally known as “off-axis” printing units. A representative, non-limiting off-axis ink delivery system is discussed in, for example, U.S. Pat. No. 5,975,686 to Hauck et al. which is also incorporated herein by reference. The present invention as described below (which involves a plurality of novel ink-receiving print media products) is applicable to both on-board and off-axis systems (as well as any other types which include at least one ink containment vessel that is either directly or remotely in fluid communication with a printhead containing one or more ink-ejecting resistors therein). Furthermore, while the print media materials outlined herein will be discussed with primary reference to thermal inkjet technology, it shall be understood that they may be employed in connection with other ink delivery systems and methods including but not limited to piezoelectric drop devices of the variety disclosed in U.S. Pat. No. 4,329,698 to Smith and dot matrix units of the type described in U.S. Pat. No. 4,749,291 to Kobayashi et al., as well as other comparable and diverse systems designed to deliver ink using one or more ink delivery components and assemblies. In this regard, the claimed print media products and methods shall not be considered “print method-specific” or “ink-specific”.
In order to effectively generate printed images using the various ink transfer techniques and systems discussed herein (again, with primary but not necessarily exclusive reference to thermal inkjet technology), ink-receiving print media materials must be employed which are capable of efficiently accomplishing this goal. Ideally, to achieve maximum efficiency, print media materials should be able to provide numerous advantages and benefits including but not limited to (1) a high level of light-fastness, with the term “light-fastness” being generally defined herein to involve the capacity of a print media product to retain images thereon in a stable fashion without substantial fading, blurring, distortion, and the like over time in the presence of natural or made-made light; (2) rapid drying times in order to avoid smudging and image deterioration immediately after printing is completed due to contact with physical objects and the like; (3) the fast and complete absorption of ink materials in a manner which avoids image distortion caused by color bleed (namely, the undesired migration of multi-colored ink components into each other) and related difficulties; (4) a highly water-fast character (with the term “water-fast” being generally defined to involve the ability of a print media product to produce a stable image with little or no fading, run-off, distortion, and the like when the image is placed in contact with moisture); (5) the generation of “crisp” images with a distinct and defined character; (6) the ability to produce printed products which are substantially “smear-fast”, with this term being generally defined to comprise the production of images that will not exhibit smearing, blurring, and the like when rubbed or otherwise physically engaged with a variety of objects ranging from the components of the printing apparatus being employed to the print operator's hands, fingers, and the like; (7) the control of an undesired condition known as “ink-coalescence” which is defined herein to involve a phenomenon wherein wet ink droplets applied to a printing medium fail to spread sufficiently to eliminate the unprinted (e.g. open) space between the droplets, thereby causing significant image deterioration problems; (8) the capacity to generate printed images with desired levels of gloss wherein the final product is characterized by uniform gloss levels throughout the entire image in order to achieve a professional and aesthetically-pleasing printed media sheet; (9) the ability to attain a high level of consistency during large-scale production regarding the overall surface characteristics of the completed media products; (10) low material costs which enable the print media products of interest to be employed for mass market home and business use; (11) chemical compatibility with a wide variety of ink formulations which leads to greater overall versatility; (12) excellent levels of image stability and retention over long time periods; (13) minimal complexity from a production, material-content, and layer-number standpoint (with as few required layers as possible being desirable) which leads to reduced fabrication costs and greater product reliability; and (14) a high level of gloss-control which is achievable in a rapid and effective manner during production through only minor adjustments in the manufacturing process. The term “gloss-control” is generally defined herein to involve the ability, during fabrication, to generate a print media product having high-gloss levels for the production of photographic quality images if desired, a semi-gloss character if needed, or other gloss parameters. In particular, the manufacturing process should be highly controllable in order to achieve a variety of different gloss characteristics without requiring major adjustments in processing steps and materials.
In the past, many different print media sheets using a wide variety of ingredients, production techniques, layering arrangements, and the like have been fabricated for a multitude of specific purposes. For example, as generally discussed in the representative patent documents listed below, the following items have been investigated and/or employed in the manufacture of print media products to achieve a broad spectrum of goals: modifications in the types of materials being used, the amounts of such materials, the relative particle sizes thereof, the particular layering arrangements being chosen, the specific combinations of ingredients being selected for layer-formation (e.g. binders, pigments, fillers, and/or other ingredients), and the adjustment of various factors including pore size, pore volume, layer thickness, particle orientation, surface roughness, surface rigidity, air permeability, and numerous other parameters. Representative patents (incorporated herein by reference) which discuss at least one or more of the above-listed factors (and/or others) are as follows: U.S. Pat. Nos. 4,391,850; 4,440,827; 4,446,174; 4,474,847; 4,567,096; 4,623,557; 4,642,247; 4,707,406; 4,780,356; 4,785,313; 4,879,166; 4,892,787; 5,008,231; 5,013,603; 5,075,153; 5,091,359; 5,093,159; 5,104,730; 5,194,347; 5,264,275; 5,266,383; 5,354,634; 5,397,619; 5,397,674; 5,463,178; 5,472,773; 5,514,636; 5,515,093; 5,665,504; 5,576,088; 5,605,750; 5,609,964; 5,635,297; 5,691,046; 5,723,211; 5,728,427; 5,744,273; 5,753,588; 5,755,929; 5,759,727; 5,798,397; 5,804,293; 5,846,637; 5,863,648; 5,882,388; 5,888,367; 5,897,961; 5,912,071; 5,916,673; 5,919,552; 5,928,789; 5,962,124; 5,965,244; 5,977,019; 5,985,076; 6,040,060; 6,063,489; 6,086,738; 6,089,704; 6,197,880; and 6,214,449.
Notwithstanding the various media products discussed in the above-listed patents and prior activities in this field, a need remains for print media materials (namely, ink-receiving sheets) which are able to capture and retain clear, distinct, and accurate images thereon that are likewise characterized by a number of specific benefits in combination. These benefits include but are not limited to items [1]-[14] recited above both on an individual and simultaneous basis in a substantially automatic manner (with the simultaneous achievement of such goals being of particular importance and novelty). The attainment of these objectives is especially important regarding the following specific items: water-fastness (with particular reference to the achievement of this goal in a pigment system containing boehmite, pseudo-boehmite, or a mixture thereof), excellent light-fastness, rapid drying time, an effective level of ink-coalescence control, and the generation of clear, durable, smear-fast, and distinct printed images. The present invention and its various embodiments perform all of the functions recited above in a uniquely effective and simultaneous manner while using a minimal number of material layers, chemical compositions, and production steps. In particular (as will become readily apparent from the discussion provided herein), the foregoing advantages and attributes are achieved through the employment of at least one ink-receiving layer having some very special ingredient combinations therein, the use of which in a print media product is entirely novel and offers the above-listed benefits. As a result, print media structures of minimal complexity are created that nonetheless exhibit a substantial number of beneficial characteristics and features in an unexpectedly efficient fashion. In this regard, the present invention represents a distinctive and important advance in the print media and image generation fields. Specific information concerning the novel print media materials of the invention and specialized fabrication methods associated therewith (which are equally unique) will be presented below in the following Summary of the Invention, Brief Description of the Drawings, and Detailed Description of Preferred Embodiments Sections.